This application claims priority under 35 U.S.C. xc2xa7119 of FR-01/11139, filed Aug. 27, 2001, assigned to the assignee hereof and hereby expressly incorporated by reference.
1. Technical Field of the Invention
This present invention relates to cosmetic or dermatological compositions suited for topical application, in particular for UV-photoprotecting human skin and hair, comprising, formulated into a cosmetically acceptable support (vehicle, diluent or carrier),
(a) at least one UV screening agent of the dibenzoylmethane derivative type, and
(b) a photostabilizing amount therefor of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
This invention also relates to a process for improving the stability of at least one dibenzoylmethane compound with respect to UV radiation, which entails combining said dibenzoylmethane compound with an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
2. Description of the Prior Art
It is known to this art that light radiation having wavelengths of from 280 nm to 400 nm permits tanning of the human epidermis and that light rays having wavelengths more particularly from 280 to 320 nm, known as UV-B radiation, cause skin burns and erythema which can harm the development of a natural tan. For these reasons, as well as for aesthetic reasons, there is a constant demand for means of controlling this natural tanning in order, thus, to control the color of the skin; this UV-B radiation should thus be screened from the skin.
It is also known that UV-A radiation, having wavelengths from 320 to 400 nm, which causes tanning of the skin, is apt to induce adverse changes therein, in particular in the case of sensitive skin or skin which is continually exposed to solar radiation. UV-A rays cause, in particular, a loss of elasticity of the skin and the appearance of wrinkles promoting premature aging of the skin. They promote triggering of the erythemal reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons such as the conservation of the skin""s natural elasticity, for example, an increasingly large number of individuals wish to control the effect of UV-A radiation on their skin. It is thus desirable to also screen out UV-A radiation.
Thus, with the goal of ensuring the most complete and most effective protection possible for the skin and the hair against the entire UV radiation spectrum, combinations of screening agents which are active in the UVA range and of screening agents which are active in the UVB range are generally formulated into sunscreen/antisun compositions.
In this respect, one particularly advantageous family of UV-A screening agents currently in favor includes dibenzoylmethane derivatives, and in particular 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane, which have high intrinsic absorbing power. These dibenzoylmethane derivatives, which are compounds which are now well known per se as screening agents that are active in the UV-A range, are described, in particular, in FR-A-2,326,405 and FR-A-2,440,933, as well as in EP-A-0,114,607; 4-(tert-butyl)-4xe2x80x2-methoxydibenzoyl-methane is moreover currently marketed under the trademark xe2x80x9cParsol 1789xe2x80x9d by Hoffmann la Roche.
Unfortunately, it has been determined that dibenzoylmethane derivatives are compounds that are relatively sensitive to ultraviolet radiation (especially UV-A), i.e., more specifically, they have an annoying tendency to be degraded more or less quickly under the influence of this UV. Thus, this substantial lack of photochemical stability of dibenzoylmethane derivatives towards ultraviolet radiation, to which they are by nature intended to be subjected, does not make it possible to ensure constant protection during prolonged exposure to the sun, and so the user must make repeated applications at regular and close time intervals in order to obtain effective protection of the skin against UV rays.
1,3,5-Triazine derivatives are particularly desired in sunscreen/antisun cosmetics due to the fact that they are highly active in the UV-B range, and even in the UV-A range for certain of these compounds depending on the nature of the substituents involved. They are especially described in U.S. Pat. No. 4,367,390, EP-863,145, EP-517,104, EP-570,838, EP-507,691, EP-796,851, EP-775,698, EP-878,469 and EP-933,376, and the following are recognized, in particular:
2,4,6-tris[p-(2xe2x80x2-ethylhexyl-1xe2x80x2-oxycarbonyl)anilino]-1,3,5-triazine or xe2x80x9cEthylhexyl Triazonexe2x80x9d (INCI name), marketed under the trademark xe2x80x9cUvinul T 150xe2x80x9d by the company BASF, and
2-[(p-(tert-butylamido)anilino]-4,6-bis[(p-(2xe2x80x2ethylhexyl-1xe2x80x2-oxycarbonyl)anilino]-1,3,5-triazine or xe2x80x9cDiethylhexyl Butamido Triazonexe2x80x9d (INCI name), marketed under the trademark xe2x80x9cUvasorb HEBxe2x80x9d by Sigma 3V.
However, it has been determined that when these 1,3,5-triazine derivatives are in the presence of dibenzoylmethane derivatives, in particular 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane, and under UV radiation, they present the drawback of undergoing substantial chemical degradation. Under these conditions, the combination of the two screening agents no longer provides a prolonged broad sunscreen/antisun protection to the skin and the hair.
It has now surprisingly and unexpectedly been determined that by combining with the dibenzoylmethane compounds indicated above an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, a substantial and noteworthy improvement in the photochemical stability (or photostability) of these same dibenzoylmethane derivatives is attained.
Furthermore, it too has been determined that incorporation of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane into a composition containing a combination of a dibenzoylmethane derivative with at least one 1,3,5-triazine derivative markedly enhances the photostability of this 1,3,5-triazine derivative in such compositions, and thus the overall efficacy thereof.
Accordingly, a major object of the present invention is the provision of cosmetic or dermatological compositions for topical application, comprising, formulated into a cosmetically acceptable support:
(a) at least one UV screening agent of the dibenzoylmethane derivative type, and
(b) an effective photostabilizing amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
The present invention also features a process for improving the stability of at least one dibenzoylmethane compound in respect of UV radiation, which comprises combining said dibenzoylmethane derivative with an effective photostabilizing amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
The present invention thus features cosmetic or dermatological compositions for topical application, comprising, formulated into a cosmetically acceptable support:
(a) at least one UV screening agent of the dibenzoylmethane derivative type,
(b) at least one UV screening agent of the 1,3,5-triazine derivative type, and
(c) an effective amount of 1,1,1-tris(2-methyl4-hydroxy-5-tert-butylphenyl)butane.
Too, this invention features a process for improving the stability of at least one 1,3,5-triazine derivative in the presence of at least one dibenzoylmethane derivative vis-à-vis UV radiation, by adding thereto an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
Thus, the present invention features including 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane in cosmetic and dermatological compositions comprising at least one dibenzoylmethane derivative, for purpose of improving the stability of said dibenzoylmethane derivative versus UV irradiation.
Lastly, the present invention features incorporating 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane into cosmetic or dermatological compositions comprising at least one dibenzoylmethane derivative and at least one 1,3,5-triazine derivative, for improving the stability of said 1,3,5-triazine derivative contained therein versus UV irradiation.
More particularly according to the present invention, by the expression xe2x80x9ceffective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane in accordance with the inventionxe2x80x9d is intended an amount that is sufficient to provide an appreciable and significant improvement in the photostability of the dibenzoylmethane derivative(s) (or of the 1,3,5-triazine derivative(s)) of the photoprotective cosmetic composition. This minimum amount of photostabilizer to be formulated, which may vary depending on the nature of the cosmetically acceptable support selected for the composition, may be determined without any difficulty by means of a standard test of photostability measurement.
The 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane compound corresponds to the following formula: 
The 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane compound is preferably present in the compositions of the invention in proportions ranging from 0.1% to 15% by weight and more preferably from 0.2% to 10% by weight relative to the total weight of the composition.
As indicated above, the dibenzoylmethane derivatives to be photostabilized in the context of the present invention are compounds that are already well known per se and described, especially, in FR-2,326,405, FR-2,440,933 and EP-0,114,607, hereby expressly incorporated by reference.
According to the present invention, one or more dibenzoylmethane derivatives may be employed.
Among the dibenzoylmethane derivatives according to the present invention, especially representative are:
2-methyldibenzoylmethane,
4-methyldibenzoylmethane,
4-isopropyldibenzoylmethane,
4-tert-butyldibenzoylmethane,
2,4-dimethyldibenzoylmethane,
2,5-dimethyldibenzoylmethane,
4,4xe2x80x2-diisopropyldibenzoylmethane,
4,4xe2x80x2-dimethoxydibenzoylmethane,
4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane,
2-methyl-5-isopropyl-4xe2x80x2-methoxydibenzoylmethane,
2-methyl-5-tert-butyl-4xe2x80x2-methoxydibenzoylmethane,
2,4-dimethyl-4xe2x80x2-methoxydibenzoylmethane, and
2,6-dimethyl-4-tert-butyl-4xe2x80x2-methoxydibenzoyl-methane.
Among the dibenzoylmethane compounds indicated above, most particularly preferred according to the present invention is 4-(tert-butyl)-4xe2x80x2-methoxydibenzoylmethane, especially the product marketed under the trademark xe2x80x9cParsol 1789xe2x80x9d by Hoffmann la Roche, this screening agent thus corresponding to the following structural formula: 
Another dibenzoylmethane derivative that is preferred according to the present invention is 4-isopropyldibenzoylmethane, a screening agent marketed under the trademark xe2x80x9cEusolex 8020xe2x80x9d by Merck, and corresponding to the following structural formula: 
The dibenzoylmethane derivative(s) may be present in the compositions in accordance with the invention in contents preferably ranging from 0.1% to 15% by weight and more preferably from 0.5% to 10% by weight relative to the total weight of the composition.
Among the 1,3,5-triazine derivatives that are useful according to the present invention, preferred are those corresponding to formula (I) below: 
in which the radicals A1, A2 and A3, which may be identical or different, are each selected from the groups of formula (II): 
wherein the radicals Xa, which may be identical or different, are each oxygen or an xe2x80x94NH-group; the radicals Ra, which may be identical or different, are each hydrogen, an alkali metal, an ammonium radical optionally substituted with one or more alkyl or hydroxyalkyl radicals, a linear or branched C1-C18 alkyl radical, a C5-C12 cycloalkyl radical optionally substituted with one or more C1-C4 alkyl radicals, a polyoxyethylenated radical comprising from 1 to 6 ethylene oxide units, the terminal OH group of which is methylated, a radical of formula (III), (IV) or (V) below: 
in which R1 is hydrogen or a methyl radical; R2 is a C1-C9 alkyl radical; q is an integer ranging from 0 to 3; r is an integer ranging from 1 to 10; A is a C4-C8 alkyl radical, or a C5-C8 cycloalkyl radical; and B is a linear or branched C1-C8 alkyl radical, a C5-C8 cycloalkyl radical, or an aryl radical optionally substituted with one or more C1-C4 alkyl radicals.
A first family of 1,3,5-triazine derivatives that is more particularly preferred is described especially in EP-A-0,517,104, and is that of the 1,3,5-triazines corresponding to formula (I) in which A1, A2 and A3 are of formula (II) and have the following characteristics:
one of the groups Xaxe2x80x94Ra is a radical xe2x80x94NHxe2x80x94Ra wherein Ra is a C5-C12 cycloalkyl radical optionally substituted with one or more C1-C4 alkyl radicals, or a radical of formula (III), (IV) or (V) above in which B is a C1-C4 alkyl radical; R2 is a methyl radical; the other 2 groups Xaxe2x80x94Ra are each a radical xe2x80x94Oxe2x80x94Ra wherein Ra, which may be identical or different, are each hydrogen, an alkali metal, an ammonium radical optionally substituted with one or more alkyl or hydroxyalkyl radicals, a linear or branched C1-C18 alkyl radical, a C5-C12 cycloalkyl radical optionally substituted with one or more C1-C4 alkyl radicals, or a radical of formula (III), (IV) or (V) above in which B is a C1-C4 alkyl radical, and R2 is a methyl radical.
A second family of 1,3,5-triazine derivatives that is more particularly preferred is described especially in EP-A-0,570,838, i.e., 1,3,5-triazines corresponding to formula (I) in which A1, A2 and A3 are of formula (II) and have all of the following characteristics:
one or two groups Xaxe2x80x94Ra is a radical xe2x80x94NHxe2x80x94Ra, wherein Ra is a linear or branched C1-C18 alkyl radical; a C5-C12 cycloalkyl radical optionally substituted with one or more C1-C4 alkyl radicals; or a radical of formula (III), (IV) or (V) above in which B is a C1-C4 alkyl radical; R2 is a methyl radical; and the other or the other two group(s) Xaxe2x80x94Ra being a radical xe2x80x94Oxe2x80x94Ra wherein the groups Ra, which may be identical or different, are each hydrogen, an alkali metal, an ammonium radical optionally substituted with one or more alkyl or hydroxyalkyl radicals, a linear or branched C1-C18 alkyl radical, a C5-C12 cycloalkyl radical optionally substituted with one or more C1-C4 alkyl radicals, a radical of formula (III), (IV) or (V) above in which B is a C1-C4 alkyl radical, and R2 is a methyl radical.
A 1,3,5-triazine of this second family that is particularly preferred is 2-[(p-(tert-butylamido)-anilino]-4,6-bis [(p-(2xe2x80x2-ethylhexyl-1xe2x80x2-oxycarbonyl)-anilino]-, 3,5-triazine or xe2x80x9cDiethylhexyl Butamido Triazonexe2x80x9d marketed under the trademark xe2x80x9cUvasorb HEBxe2x80x9d by Sigma 3V and corresponding to the following formula: 
in which Rxe2x80x2 denotes a 2-ethylhexyl radical and R denotes a tert-butyl radical.
A third preferred family of compounds that is suited for formulation into the compositions of the present invention is particularly described in U.S. Pat. No. 4,724,137, i.e., the 1,3,5-triazines corresponding to formula (I) in which A1, A2 and A3 are of formula (II) and have the following characteristics:
Xa are identical and represent oxygen;
the groups Ra, which may be identical or different, are each a C6-C12 alkyl radical or a polyoxyethylenated radical comprising from 1 to 6 ethylene oxide units and in which the terminal OH group is methylated.
A 1,3,5-triazine of this third family that is particularly preferred is 2,4,6-tris[p-(2xe2x80x2-ethylhexyl-1xe2x80x2-oxycarbonyl)anilino]-1,3,5-triazine or xe2x80x9cEthylhexyl Triazonexe2x80x9d marketed, especially, under the trademark xe2x80x9cUvinul T 150xe2x80x9d by BASF and corresponds to the following formula: 
in which Rxe2x80x2 is a 2-ethylhexyl radical.
The 1,3,5-triazine derivative(s) is (are) generally present in the compositions of the invention in a content that can range from 0.1% to 15% and preferably from 0.5% to 10% by weight relative to the total weight of the composition.
The compositions in accordance with the invention may also comprise other additional organic UV screening agents that are active in the UVA and/or UVB range (absorbers), which are water-soluble or liposoluble or even insoluble in the cosmetic solvents commonly used.
The additional organic UV screening agents are especially selected from among anthranilates; salicylic derivatives; camphor derivatives; benzophenone derivatives; xcex2,xcex2-diphenylacrylate derivatives; benzotriazole derivatives; benzalmalonate derivatives; benzimidazole derivatives; triazine derivatives other than those of formula (I) indicated above; imidazolines; bis-benzazolyl derivatives as described in EP-669,323 and U.S. Pat. No. 2,463,264; p-aminobenzoic acid (PABA) derivatives; methylenebis(hydroxyphenyl)benzotriazole derivatives as described in U.S. Pat. Nos. 5,237,071, 5,166,355, GB-2,303,549, DE-197,26,184 and EP-893,119; screening polymers and screening silicones such as those particularly described in WO-93/04665; dimers derived from xcex1-alkylstyrene, such as those described in DE-198,55,649, 4,4-diarylbutadienes such as those described in EP-0,967,200 and DE-197,55,649 (each hereby expressly incorporated by reference).
Exemplary UV-A-active and/or UV-B-active additional organic screening agents include the following, denoted hereinbelow under their INCI name:
Para-Aminobenzoic Acid Derivatives
PABA,
Ethyl PABA,
Ethyl dihydroxypropyl PABA,
Ethylhexyl dimethyl PABA marketed, in particular, under the trademark xe2x80x9cEscalol 507xe2x80x9d by ISP,
Glyceryl PABA,
PEG-25 PABA marketed under the trademark xe2x80x9cUvinul P25xe2x80x9d by BASF.
Salicylic Derivatives
Homosalate marketed under the trademark xe2x80x9cEusolex HMSxe2x80x9d by Rona/EM Industries,
Ethylhexyl salicylate marketed under the trademark xe2x80x9cNeo Heliopan OSxe2x80x9d marketed by Haarmann and Reimer,
Dipropylene glycol salicylate marketed under the trademark xe2x80x9cDipsalxe2x80x9d by Scher,
TEA salicylate marketed under the trademark xe2x80x9cNeo Heliopan TSxe2x80x9d by Haarmann and Reimer.
xcex2,xcex2xe2x80x2-Diphenyl Acrylate Derivatives
Octocrylene marketed, in particular, under the trademark xe2x80x9cUvinul N539xe2x80x9d by BASF,
Etocrylene marketed, in particular, under the trademark xe2x80x9cUvinul N35xe2x80x9d by BASF.
Benzophenone Derivatives
Benzophenone-1 marketed under the trademark xe2x80x9cUvinul 400xe2x80x9d by BASF,
Benzophenone-2 marketed under the trademark xe2x80x9cUvinul D50xe2x80x9d by BASF,
Benzophenone-3 or Oxybenzone marketed under the trademark xe2x80x9cUvinul M40xe2x80x9d by BASF,
Benzophenone-4 marketed under the trademark xe2x80x9cUvinul MS40xe2x80x9d by BASF,
Benzophenone-5,
Benzophenone-6 marketed under the trademark xe2x80x9cHelisorb 11xe2x80x9d by Norquay,
Benzophenone-8 marketed under the trademark xe2x80x9cSpectra-Sorb UV-24xe2x80x9d by American Cyanamid,
Benzophenone-9 marketed under the trademark xe2x80x9cUvinul DS-49xe2x80x9d by BASF,
Benzophenone-12.
Benzylidenecamphor Derivatives
4-Methylbenzylidenecamphor marketed under the trademark xe2x80x9cEusolex 6300xe2x80x9d by Merck,
3-Benzylidenecamphor marketed under the trademark xe2x80x9cMexoryl SDxe2x80x9d by Chimex,
Benzylidenecamphorsulfonic acid marketed under the trademark xe2x80x9cMexoryl SLxe2x80x9d by Chimex,
Camphor benzalkonium methosulfate marketed under the trademark xe2x80x9cMexoryl SOxe2x80x9d by Chimex,
Terephthalylidenedicamphorsulfonic acid marketed under the trademark xe2x80x9cMexoryl SXxe2x80x9d by Chimex,
Polyacrylamidomethylbenzylidenecamphor marketed under the trademark xe2x80x9cMexoryl SWxe2x80x9d by Chimex.
Benzimidazole Derivatives
Phenylbenzimidazolesulfonic acid marketed, in particular, under the trademark xe2x80x9cEusolex 232xe2x80x9d by Merck,
Disodium phenyldibenzimidazole tetrasulfonate marketed under the trademark xe2x80x9cNeo Heliopan APxe2x80x9d by Haarmann and Reimer.
Triazine Derivatives
Anisotriazine marketed under the trademark xe2x80x9cTinosorb Sxe2x80x9d by Ciba Geigy, 2,4,6-tris-(diisobutyl 4xe2x80x2-amino-benzalmalonate)-s triazine.
Benzotriazole Derivatives
Methylenebis(benzotriazolyl)tetramethylbutylphenol marketed in solid form under the trademark xe2x80x9cMixxim BB/100xe2x80x9d by Fairmount Chemical, or in micronized form as an aqueous dispersion under the trademark xe2x80x9cTinosorb Mxe2x80x9d by Ciba Specialty Chemicals,
Drometrizole trisiloxane marketed under the trademark xe2x80x9cSilatrizolexe2x80x9d by Rhodia Chimie.
Anthranilic Derivatives
Menthyl anthranilate marketed under the trademark xe2x80x9cNeo Heliopan MAxe2x80x9d by Haarmann and Reimer.
Imidazoline Derivatives
Ethylhexyldimethoxybenzylidenedioxoimidazoline propionate.
Benzalmalonate Derivatives
Polyorganosiloxane containing benzalmalonate functional groups marketed under the trademark xe2x80x9cParsol SLXxe2x80x9d by Hoffmann La Roche and mixtures thereof.
The additional organic UV screening agents that are more particularly preferred are selected from among the following compounds:
Ethylhexyl salicylate,
Octocrylene,
Phenylbenzimidazolesulfonic acid,
4-Methylbenzylidenecamphor,
Disodium phenyldibenzimidazole tetrasulfonate,
Terephthalylidenedicamphorsulfonic acid,
Anisotriazine,
2,4,6-Tris-(4xe2x80x2-Amino-benzalmalonatediisobutyl)-s-triazine,
Benzophenone-3,
Benzophenone-4,
Benzophenone-5,
Methylenebis(benzotriazolyl)tetramethylbutylphenol,
n-Hexyl 2-(4-diethylamino-2-hydroxybenzoyl)-benzoate
Drometrizole trisiloxane, and mixtures thereof.
The cosmetic compositions according to the invention may also comprise pigments or nanopigments (average size of the primary particles: generally ranging from 5 nm to 100 nm and preferably from 10 nm to 50 nm) of coated or uncoated metal oxides, such as, for example, nanopigments of titanium dioxide (amorphous or crystallized in rutile and/or anatase form), of iron oxide, of zinc oxide, of zirconium oxide or of cerium oxide, which are all UV photoprotective agents that are well known per se. Standard coating agents are, moreover, alumina and/or aluminum stearate. Such coated or uncoated metal oxide nanopigments are described, in particular, in EP-A-0,518,772 and EP-A-0,518,773.
The compositions according to the invention may also contain agents for artificially tanning and/or browning the skin (self-tanning agents) such as, for example, dihydroxyacetone (DHA).
The compositions of the invention may also comprise standard cosmetic additives and adjuvants selected especially from among fatty substances, organic solvents, ionic or nonionic thickeners, softeners, antioxidants, free-radical scavengers, opacifiers, stabilizers, emollients, silicones, xcex1-hydroxy acids, antifoams, moisturizers, vitamins, insect repellants, fragrances, preservatives, surfactants, anti-inflammatories, substance P antagonists, fillers, polymers, propellants, acidifying or basifying agents, colorants or any other ingredient usually formulated into cosmetics, in particular for the production of sunscreen compositions in the form of emulsions.
The fatty substances may be an oil or a wax or mixtures thereof, and they also comprise linear or cyclic fatty acids, fatty alcohols and fatty acid esters such as benzoic, trimellitic and hydroxybenzoic acid derivatives. The oils may be selected from among animal, plant, mineral and synthetic oils and especially from liquid petroleum jelly, liquid paraffin, volatile or non-volatile silicone oils, isoparaffins, polyolefins, fluoro oils and perfluoro oils. Similarly, the waxes may be animal, fossil, plant, mineral and synthetic waxes that are known per se.
Among the organic solvents, exemplary are the lower alcohols and polyols.
Of course, one skilled in this art will take care to select this or these optional additional compound(s) and/or the amounts thereof such that the advantageous properties, in particular the photostability, intrinsically associated with the compositions in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).
The compositions of the invention may be formulated according to techniques that are well known to this art, in particular those intended for preparing emulsions of oil-in-water or water-in-oil type.
These compositions may be, in particular, in the form of a simple emulsion or a complex emulsion (O/W, W/O, O/W/O or W/O/W), such as a cream, a milk, a lotion, a gel or a cream-gel, a powder or a solid tube, and may optionally be packaged as an aerosol and may be in the form of a mousse or spray.
When it is an emulsion, the aqueous phase of this emulsion may comprise a nonionic vesicular dispersion prepared according to known processes (Bangham, Standish and Watkins, J. Mol. Biol. 13, 238 (1965), FR-2,315,991 and FR-2,416,008).
The cosmetic compositions of the invention are useful for protecting the human epidermis or the hair against the damaging effects of ultraviolet rays, as sunscreen/antisun compositions or as makeup products.
When the cosmetic composition according to the invention is used for protecting the human epidermis against UV radiation, or as an antisun/sunscreen composition, it may be in the form of a suspension or a dispersion in solvents or fatty substances, in the form of a nonionic vesicular dispersion, or in the form of an emulsion, preferably of oil-in-water type, such as a milk, lotion or a cream, or in the form of an ointment, a gel, a cream-gel, a solid tube, a powder, a stick, an aerosol mousse or a spray.
When the cosmetic composition according to the invention is used for protecting the hair against UV rays, it may be formulated as a shampoo, a lotion, a gel, an emulsion or a nonionic vesicular dispersion and may constitute, for example, a rinse-out composition, to be applied before or after shampooing, before or after dyeing or bleaching, or before, during or after permanent-waving or straightening the hair, a styling or treating lotion or gel, a blow-drying or hairsetting lotion or gel, or a permanent-waving, straightening, dyeing or bleaching composition for the hair.
When the composition is suited as a makeup product for the eyelashes, the eyebrows or the skin, such as an epidermal treatment cream, a foundation, a tube of lipstick, an eyeshadow, a face powder, mascara or an eyeliner, it may be in solid or pasty, anhydrous or aqueous form, for example oil-in-water or water-in-oil emulsions, nonionic vesicular dispersions or suspensions.
For example, for the sunscreen/antisun formulations in accordance with the invention that contain a support of oil-in-water emulsion type, the aqueous phase (especially comprising the hydrophilic screening agents) generally constitutes from 50% to 95% by weight and preferably from 70% to 90% by weight, relative to the total weight of the formulation, the oily phase (especially comprising the lipophilic screening agents) from 5% to 50% by weight and preferably from 10% to 30% by weight, relative to the total weight of the formulation, and the (co)emulsifier(s) from 0.5% to 20% by weight and preferably from 2% to 10% by weight, relative to the total weight of the formulation.
As indicated above, the present invention features compositions cosmetic or dermatological applications for protecting the skin and/or the hair against ultraviolet radiation, in particular solar radiation.
This invention also features improving the stability of at least one dibenzoylmethane compound in respect as UV radiation protection, which entails combining such dibenzoylmethane compound with an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane as defined above.
The present invention also features 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane into cosmetic or dermatological compositions comprising at least one UV screening agent of the dibenzoylmethane derivative type, for the purpose of improving the stability of said dibenzoylmethane compound in respect of UV radiation.
Too, this invention, thus, also features a regime or regimen for UV-photoprotecting human skin and/or hair against the damaging effects of UV-radiation, by topically applying thereon, for such period of time as required to provide the desired UV-photoprotective effect, any of the subject UV-photoprotecting cosmetic/dermatological compositions.